Mechanism for moving movie projector film intermittently in normal and reverse directions

ABSTRACT

A mechanism for moving film intermittently in normal and reverse directions, for a movie projector of the type having a film feed member operated by first and second cams, with the first cam reciprocating the feed member longitudinally of the film and the second cam reciprocating the feed member toward and away from the film, the two cams being driven by a shutter operating shaft, includes a follower interposed between the film feed member and the second cam. The direction in which the film is moved by the feed member can be switched between normal and reverse by shifting the follower on the surface of the second cam through an angle of at least 120* with respect to the axis of the cam. The angle through which the follower is shifted varies in dependence on the number of blades of the shutter of the projector.

United States Patent Kurasawa [54] MECHANISM FOR MOVING MOVIE PROJECTORFILM INTERMI'ITENTLY IN NORMAL AND REVERSE DIRECTIONS [72] Inventor:Makoto Kurasawa, Tokyo, Japan [73] Assignee: Kabushiki Kaisha Ricoh,Tokyo,

Japan 221 Filed: Nov. 5, 1970 21 Appl.No.: 8 7,275

[30] Foreign Application Priority Data [451 Oct. 3, 1972 3,583,8016/1971 Roth ..352/173 3,520,596 7/1970 ODonnell et a1. ..352/923,460,730 8/ 1969 Krumbein ..226/64 3,402,006 9/ 1968 Bundschuh et al....352/ 194 X 3,537,629 11/1970 Riedel ..352/196 X 3,261,654 7/1966Faber et al ..352/194 Primary ExaminerSamuel S. Matthews AssistantExaminer-Alan A. Mathews Attorney-McGlew and Toren ABSTRACT A mechanismfor moving film intermittently in normal and reverse directions, for amovie projector of the type having a film feed member operated by firstand second cams, with the first cam reciprocating the feed memberlongitudinally of the film and the second cam reciprocating the feedmember toward and away from the film, the two cams being driven by ashutter operating shaft, includes a follower interposed between the filmfeed member and the second cam. The direction in which the film is movedby the feed member can be switched between normal and reverse byshifting the follower on the surface of the second cam through an angleof at least 120 with respect to the axis of the cam. The angle throughwhich the follower is shifted varies in dependence on the number ofblades of the shutter of the projector.

3 Clains, 4 Drawing Figures PATENTEDHBI 3 I972 3. 695. 753

INVENTOR.

MAKOTO KURASAWA m gawamom ATTO R NEYS MECHANISM FOR MOVING MOVIEPROJECTOR FILM INTERMITTENTLY IN NORMAL AND REVERSE DIRECTIONSBACKGROUND OF THE INVENTION When a film is screened or projected bymoving the film in a reverse direction, in a movie-projector, such as an8 mm movie projector, for example, the film is moved intermittently inthe reverse direction past the film gate. l-leretofore, the usual mannerof screening a SUMMARY OF THE INVENTION This invention relates to movieprojectors and, more particularly, to a novel and simplified mechanismfor selectively reversing the direction of film movement without the useof a reversible motor or of a reverse mechanism interposed between amotor and a shutter operating shaft.

The invention has, for its objective, the provision, in a movieprojector of the type in which a film feed member is operated by twocams, one of which reciprocates the feed member longitudinally of thefilm path and the other of which reciprocates the feed member toward andaway from the film, with both cams being driven by a shutter operatingshaft, of a mechanism for intermittently moving the film in either thenormal or the reverse directions and which obviates the abovementioneddisadvantages of the prior art. In accordance with the invention, thisobjective is attained by interposing, between the film feed member andthe cam for moving the feed member toward and away from the film, a camfollower which is adapted to be shifted through a suitable angle on thecam surface of this cam with respect to the axis of rotation of the cam.Thereby, the film can be moved selectively intermittently in eithernormal direction or reverse direction.

In the mechanism embodying the invention, the film can be moved ineither the normal or reverse direction while the shutter main shaft oroperating shaft rotates continuously in one direction. Thereby, it isnot necessary to use a reversible motor or to provide a reverse movementmechanism between the motor and the shutter operating shaft.Consequently, the invention is conducive to reduced cost and accurateoperation of projectors. The two cams rotate in only one direction, sothat the sound provided by film movement when the film is moved in thereverse direction remains the same as that provided when the film ismoved in the normal direction. A projector embodying the invention isconvenient to use because the projector can be operated readily bysimple means, to effect reverse movement screening of the film.Furthermore, the mechanism of the present invention is so constructedthat theparts are substantially free from wobble, and consequently it isnot necessary to effect adjustments which are troublesome and timeconsuming.

While the direction of movement of the film could be reversed, inaccordance with the invention, by moving the cam, for reciprocating thefilm feed member toward and away from the film, relative to thefollower, there are technical difficulties with respect to moving thecam relative to its supporting shaft. Thus, the invention arrangement inwhich the follower is shifted relative to the cam, as describedhereinafter, is preferable because of its freedom from such technicaldifiiculties.

An object of the invention is to provide an improved film movementdirection reversing means for movie projectors.

Another object of the invention is to provide such a reversing mechanismwhich is simple, effective, and not prone to malfunction.

A further object of the invention is to provide such a reversingmechanism in which a cam follower is interposed between a cam, forreciprocating a film feed member toward and away from the film, and thefilm feed member, and is adjustable angularly of the cam surface of thecam.

Another object of the invention is to provide such a mechanism in whichshifting of the cam follower can be effected manually by simpletrouble-free means.

For an understanding of the principles of the invention, reference ismade to the following description of typical embodiments thereof asillustrated in the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is a perspective view of mechanism, embodying the invention, forfeeding film intermittently, in a movie projector, in either the normaldirection or the reverse direction;

FIG. 2 is a front elevation view showing the relative positions, duringoperation, of a first cam for reciprocating a film feed memberlongitudinally of the path of travel of the film and a second cam forreciprocating the film feed member toward and away from the film, andforming parts of the mechanism shown in FIG. 1;

FIGS. 3A and 3B are schematic views illustrating the movements of thefilm advancing claw of the feed member of the mechanism shown in FIG. 1;and

FIG. 4 is a front elevation view of another embodiment of mechanism forintermittently feeding a film in normal and reverse directions in amovie projector.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to theembodiment of the invention shown in FIGS. 1 and 2, a film l isillustrated as passing through a film gate of a movie projector, withthe film being advanced by a film feed member 2 having, at one endthereof, claws 2a and 2b arranged to be engaged in the perforations offilm l to advance the film. Feed member 2 is formed with slots 20 and 2dwhich are vertically elongated, as shown in FIG. 1, and which looselyreceive headed pins 3 and 4, respectively, secured to a fixed part (notshown) of a projector. Film feed member 2 is supported, by pins 3 and 4,for vertical reciprocation longitudinally of the direction of filmtravel and for reciprocation toward and away from film l.

A shutter main or operating shaft 5, disposed normal to the verticalplane including the surface of film 1, is positioned above film feedmember 2. Shaft 5 mounts shutter blades 6, 6 for intermittently blockingthe optical path of projected pictures, and also a cam 7 forreciprocating film feed member 2 vertically relative to film 1. For thispurpose, a pin 8 secured on film feed member 2 is disposed below cam 7and positioned against the peripheral surface thereof. Suitable meansare provided to bias member 2 in a direction to press pin 8 against theperiphery of cam 7, and shaft 5 is connected to the projector drivemechanism (not shown) by suitable means. Thus, if shutter operatingshaft 5 rotates in the direction of the arrow a, film feed member 2 isreciprocated vertically, or longitudinally of film l, by cam 7 inengagement with pin 8.

A gear 9 is secured to the front end of shaft 5, and meshes with a gear10 mounted on a shaft 11 which supports a cam 12 for moving film feedmember 2 forwardly and backwardly, or toward and away from film 1. Cam12 is rotated in the direction of arrow b, or in a direction opposite tothe direction of rotation of shutter main or operating shaft 5. That endof film feed member 2 opposite to the end having the claws 2a and 2b hasa vertically oriented leg 2e which faces the cam surface of cam 12.

In accordance with the invention, a follower 14 is interposed betweenleg 2e and the cam surface of cam 12, and is slidably supported by asleeve 13 so that it is perpendicular to the surface of leg 2e and thecam surface of cam 12. Sleeve 13 is fixedly secured to an operationmember 15 which is mounted for sliding upwardly and downwardly as viewedin FIG. 1. Operation member 15 is adapted to shift follower 14 over thecam surface of cam 12, and to hold follower 14 positively in a positionin which it rides on a protuberance 12a adjacent the peripheral marginof the cam surface of cam 12 and projecting axially of cam 12.

Suitable means are provided to cause film member 2 to press lightlyagainst follower 14 so as to press follower 14, in turn, against the camsurface of cam 12. Accordingly, as cam 12 rotates, film feed member 2 iscaused, by cam 12, through follower 14, to swing intermittentlybackwardly and forwardly, and thus toward and away from film 1. Shaft11, supporting cam 12, is cut off so that its end is flush with the camsurface of cam 12.

In FIGS. 1 and 2, the cams 7 and 12 are shown in solid lines as inrelative positions in which that end of follower 14 disposed on the camsurface of cam 12 is in the position in which it is shifted forwardlythrough 270 from the center of axial protrusion 12a when pin 8 is movedto its lowermost position by cam 7. When follower 14 is in thisposition, the movements of the film operating claws 2a and 2b of feedmember 2 are as shown in FIG. 3A, in which a dash-and-dot line indicatesthe film path. Referring to FIG. 3A, the claws 2a and 2b, during theirforward motion stroke A, engage in perforations in film 1, and advancethe film downwardly during the succeeding downward motion stroke B. Thefilm 1 is advanced by one frame during this pull-down stroke, andscreened during the remaining two strokes of the claws 2a and 2b. Thus,following the downward movement stroke B, claws 2a and 2b are retractedand disengaged from the perforations in film 1, and are then movedupwardly to complete the cycle of movement.

If operation member 15 is operated, from outside the projector, andmoved to the broken line position 15A shown in FIG. 1, with cam 7, forreciprocating feed member 2 longitudinally of film 1, and pin 8remaining in the positions shown in FIGS. 1 and 2, follower 14 will beshifted to the broken line position 14A shown in FIGS. 1 and 2. Thisbroken line position is diametrically opposite the original position offollower 14, or shifted through 180 from such original position withrespect to the axis of cam 12. When follower 14 is in the position 14A,the forward and backward strokes of claws 2a and 2b are retarded by 180with respect to their up and down strokes so that the movements of claws2a and 2b are as shown in FIG. 3B. Thus, in FIG. 3B, the directions ofmovements during one cycle are reversed from the directions of movementsshown in FIG. 3A. When this is the case, the film 1 is moved in thereverse direction during the upward stroke D of claws 2a and 2b whichare engaged in the film perforations in the preceding forward stroke C,thereby resulting in screening of film 1 while the film is moved in thereverse direction.

FIG. 4 illustrates another operating means for shifting follower 14 overthe cam surface of cam 12. In this embodiment of the invention, a sleeve41a of a support 41 for follower 14 is loosely fitted over the shaft 11mounting cam 12, and a sleeve 41b at the outer end of support 41 looselyreceives follower 14. Sleeve or bushing 410 has a minor diameter portion410 to which is secured a pinion 42 meshing with the gear 43 which, inturn, meshes with a segmental gear 44. Gear 44 is provided with anoperation handle 44a which can be operated from outside the projectorfor swinging segmental gear 44 to rotate support 41 through the mediumof gears 43 and 42.

Such rotation responsive to movement of operation handle 44a causesfollower 14 to move, on the cam surface of cam 12, about shaft 11, thuspermitting the fol lower 14 to be positioned at any location as desiredon the cam surface of cam 12. Suitable means, such as click stop means,may be provided for terminating movement of operation handle 44a andlocking the same in position, in order that follower 14 may be held inplace in any predetermined position on the cam surface of cam 12.

In the embodiment of FIG. 4, the direction of move ment of the film canbe reversed when follower 14 is shifted over the cam surface of cam 12through 180, with respect to the axis of the cam, because the shutterhas only two blades. It will be clear that, if the shutter has fourblades, then the movement of the film also can be reversed by shiftingthe follower 14 through 180, and that, if the shutter has three blades,the direction of movement of the film can be reversed by shiftingfollower 14 through either or 240.

While specific embodiments of the invention have been shown anddescribed in detail to illustrate the application of the principles ofthe invention, it will be understood that the invention may be embodiedotherwise without departing from such principles.

what is claimed is:

1. In a movie projector including a shutter, a shutter operating shaft,a film feed member having claws engageable in perforations in the film,a first cam for reciprocating the feed member longitudinally of thefilm, and a second cam for reciprocating the feed member toward and awayfrom the film to engage and disengage, respectively, perforations, withboth cams being driven from the shutter operating shaft: the improvementcomprising, in combination, a cam follower interposed between said filmfeed member and said second cam; means selectively operable to effectrelative shifting between the cam surface of said second cam and saidfollower between cam surface-follower contact positions spaced angularlyapart by at least 120, to vary the reciprocations of said film feedmember toward and away from the film, in phase, through at least 120;whereby the direction of film movement may be switched between normaland reverse directions responsive to such shifting; said means mountingsaid cam follower and selectively operable to shift the latter over thecam surface of said second cam; an externally accessible operatingmember connected to said mounting means; said second cam being acircular cam and said cam surface the claws relative to the film beingan arcuate axial protrusion of limited angular extent adjacent theperipheral margin of said second cam; a second shaft mounting saidsecond cam and rotatable from said operating shaft; said second shaftprojecting axially outwardly of that surface of said second cam engagedby said cam follower; said means mounting said cam follower comprising aradial arm rotatable about said second shaft independently of saidsecond cam, and having a sleeve at its outer end mounting said camfollower for movement axially of said sleeve; and a gear secured to saidarm coaxially with said second shaft; said operating member comprisinggear means meshing with said gear.

2. In a movie projector, the improvement claimed in claim 1, in whichsaid gear means comprises a segmental gear oscillatable to rotate saidfirst-mentioned gear and having an operating handle,

3. In a'movie projector, the improvement claimed in claim 1, in whichsaid gear is a pinion; said gear means comprising a spur gear meshingwith said pinion; said operating member comprising a segmental gearmeshing with said spur gear and having an operating handle.

1. In a movie projector including a shutter, a shutter operating shaft,a film feed member having claws engageable in perforations in the film,a first cam for reciprocating the feed member longitudinally of thefilm, and a second cam for reciprocating the feed member toward and awayfrom the film to engage and disengage, respectively, the claws relativeto the film perforations, with both cams being driven from the shutteroperating shaft: the improvement comprising, in combination, a camfollower interposed between said film feed member and said second cam;means selectively operable to effect relative shifting between the camsurface of said second cam and said follower between camsurface-follower contact positions spaced angularly apart by at least120*, to vary the reciprocations of said film feed member toward andaway from the film, in phase, through at least 120*; whereby thedirection of film movement may be switched between normal and reversedirections responsive to such shifting; said means mounting said camfollower and selectively operable to shift the latter over the camsurface of said seconD cam; an externally accessible operating memberconnected to said mounting means; said second cam being a circular camand said cam surface being an arcuate axial protrusion of limitedangular extent adjacent the peripheral margin of said second cam; asecond shaft mounting said second cam and rotatable from said operatingshaft; said second shaft projecting axially outwardly of that surface ofsaid second cam engaged by said cam follower; said means mounting saidcam follower comprising a radial arm rotatable about said second shaftindependently of said second cam, and having a sleeve at its outer endmounting said cam follower for movement axially of said sleeve; and agear secured to said arm coaxially with said second shaft; saidoperating member comprising gear means meshing with said gear.
 2. In amovie projector, the improvement claimed in claim 1, in which said gearmeans comprises a segmental gear oscillatable to rotate saidfirst-mentioned gear and having an operating handle.
 3. In a movieprojector, the improvement claimed in claim 1, in which said gear is apinion; said gear means comprising a spur gear meshing with said pinion;said operating member comprising a segmental gear meshing with said spurgear and having an operating handle.